This invention relates to an automatic machine for forming packaging cases.
Known are packaging cases intended for containing a variety of products, such cases being formed from cardboard sheets which are die-cut and folded onto themselves to produce tubular elements having closure flaps at their opposed ends. Such tubular elements, which are stored in a flattened condition and stacked upon one another in a magazine, are subsequently spread open to take a parallelepipedal shape and then closed by folding the end flaps over to define the bottom and cover or lid of the finished case.
Conventional machines for picking up the folded cases from the magazine and spreading them open have operational limitations, in that the atmospheric pressure tends to resist the case spreading action by preventing air from entering the case with sufficient rapidity. This problem becomes the more serious, the larger is the size of the cases being processed, so that to avoid irreversible deformation of the cases and delay at the packaging area, it becomes necessary to reduce the case spreading rate as their sizes increase.